Sectional holddown bar for endless bed sanders



Feb. 22, 1927. 1,618,207

F. L. LANE SECTIONAL HQLDDOWN BAR FOR ENDLESS BED SANDERS Filed Dec. 24, 1925 2 Sheets-Sheen Z m -4w Feb 22 1927 F. .L. LAN

SECTIONAL 'HOLDDOWN BAR FOR ENDLESS BED SANDERS- Filed Dec. 24, 1925 Q 2 Sheets-Sheetz reamed Feb. 22, 1927.

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cA pplic'ationiiled Dedember 24,1925. Serial No. 7'7,647.

less bed sanders, wherein the stock tofbe surfaced is placed on a moving bed and is carriedby the same under a hold-down bar and into co-action with one or more rapidly rotating sander drums.

-One object ofthe inventionis to providean improved hold-down bar which is capable of compensating automatically for any variations inthe thicknesses of different pieces of'stock approaching the first or, sizing drum by allowing the thicker pieces tobeacted upon by that drum to proportionately greater depths than the thinner. pieces, whereby they sizing is substantially completed by the first drum and the succeeding drums may more. effectively, accomplish the smoothing and-- polishing operations for which they are intended Another object is to provide such a holddown bar which is capable of hand-linglsimultaneously several ferent thicknesses Other objects and advantages will be evident upon 'a'full understanding, of the nature of tliehold-down bar, theinvention re,- sidingsubstantially in the novel features of construction, arrangement 3 and combination of. partsconstituting. the bar. a

A preferred form of; the invention is set forth in the accompanying drawings and following descriptionfbut it is to be under? stood that; such embodiment is presented merely for the purpose. of illustration and is not-to be accorded any interpretation which,

might be calculated to limit the invention short of its true and most comprehensive scope in' the art.

In the drawings:

Fig. 1 is a partially sectioned side eleva-i tionof an endless bed sander equipped with a hold-down bar constructed in accordance with the invention; V

Fig. 2 is a plan view of the front end of the sander, showing several pieces of stock engaged by the hold-down bar; and

Fig. 3 is a fragmentary vertical section taken longitudinally of the sander through the hold-down bar and first drum. I

It will be observed in the drawings that the sander'includes a main frame 10, a series of sander drums 11 which are rotatably mounted in bearings in the upper portion of the frame, and an endless bed 12 which pieces of stock of dif! is adjustably positioned with the upper hoi'ii peripheries of the drums.

frame 13,;and the-frame 13 is supported between theside walls of the frame lfOby suit-v able means which permit of'vertica'lqadjusb.

ment. The surface of thetbed: is composed The bed 12is mounted, on aseparate bed,

nontal, stretch of the same. spaced below.- the of a largenumber of closely, arranged rub her pads 14 which 'arc secured to a number: of transversely extending slats 15,- and; the

slats 15 areattached-to two spaced'chains 16.

which are trained over sprockets17 carried I by the frame 13. The upper stretch of; the bed 12 moves from the in-feed end18 of the sander to the out-feed end 19, and issuprv ported during such movement on a number onto theibed l2 from atable 21 which is ar-' I ranged at the extreme in-feed end of the frame 13 in alignment with thebed, and

during the successive surfacing. operations by the drums 11, the'pieces are held down upon-the resilientlyyieldable pads, 14 of the bedinproper position relative to the drumsbym'eans ofa number of transversely extendlng hold down'bars. 22-1 The bars 22arc arranged in front of, between, and behind bars at about thesaine level as the bottoms fixed guides whichfserve to press the pieces of stock against the resiliently yieldahle bed land'z thereby equallygauge, tl eiamount of material'removed from thetop surfaces of V les feckiby the oper t o ,ofvth r ms;-

fthe drums 11,With the under surfaces of the The front hold-down bar 23; is different; p

from the others, and it is in the construction, arrangement and operation of the same that this invention particularly resides.

The bar 23- -which isbestshown in Figs. 2 and 3consists of a hollow frame 24'which is secured by bolts 25 or other suitable means to the side walls of the frame 10. The bar is of sectional construction in that the bottom of the same is composed of a number of closely arranged fingers 26. The front ends of the fingers 26 pivotally engage with the frame by means of a rib and groove consprings 31 which are interposed between the I fingers and the frame. The fingers are limited in their downward spring pressed movement by lugs .32 on the frame which engage with shoulders 33 on the fingers, and are 5 limited in their upward resiliently yieldable movement by engagement of the lugs 32 with shoulders 34 on the fingers.

In the operation of the sander, the front hold-down bar 23 functions in the following manner:

The pieces of stock to be surfaced are placed on the table 21 and are carried into the sander by'the pads 14 on the bed 12. The pieces may be placed on the table in stacks, if desired, and the front face of the bar 23 will act as a hopper for automatically feeding the pieces, the latter being removed from the bottom of-the' stacks in single order and carried beneath the angle strip 28. The

number of fingers 26 engaging with each piece will, of course, depend upon the width of the latter. As the pieces move below the hold-down bar, they come into contact with the downwardly and rearwardly I inclined bottom faces 30 of the fingers and bear against the same, which causes the pieces to imbed slightly in the resiliently yieldable pads 14; If a piece is relatively thin, the fingers 26 in engagement therewith will be pressed upwardly but a slight amount, and a proportionately thin layer of the stock will be removed by the front drum in the sizing operation, while, if the piece is relatively thick, the fingers will yield a greater amount and a proportionately thick layer of the stock will be removed. As a result, the pieces of stock are brought to substantially the same thickness irrespective of their original sizes, and the actions of the succeeding drums are almost entirely smoothing and polishing ones.

I claim:

1. In a sander, the combination'with a r0- tatable drum, and an endless resiliently yieldable bed for moving pieces of stock to be surfaced into co-action with the periphery of the drum, of a. sectionalhold-down bar in advance of thedrum having resiliently be surfaced into co-action with the periphery of the drum, of means for positioning the stock relative to the drum comprising a stationary frame, and a number of resiliently yieldable fingers pivoted at their front ends to the frame and spring pressed at their rear ends from the same to provide bottom operative surfaces on the fingers for engagement with the stock.

3. In a sander, a sectional hold-down bar in advance of the drum, comprising a sta tionary frame, a plurality of closely arranged fingers interlocked at their front ends with the frame, an angle strip secured to the front face of the frame and extending beneath the front ends of the fingers for main taining loosely the interlocked engagement between the fingers and frame to effect a pivotal connection therebetween, springs interposed between the rear ends of the fingers and the frame to render the fingers resiliently yieldable to upward pressure, and co-acting shoulders on the fingers and frame for limiting the upward and downward movements of the fingers.

4. In a sander, the combination with a series of rotatable drums, and an endless bed.

for moving pieces of stock to be surfaced into co-action with each of the drums in turn, of resilient means for pressing the stock toward each of the drums, rigid means for limiting the extent to which the stock is caused by said resilient pressing --means to approach all drums except the FRANKLIN L. LANE. 

